Method for controlling illumination employed by a computer pointing peripheral and computer pointing peripheral

Abstract

In one embodiment, a method of operating a computer pointing peripheral comprises capturing images of a support surface to perform navigational analysis, analyzing at least one image characteristic, modifying an image exposure time in response to the analyzing, and modifying an intensity of illumination of the support surface when the image exposure time fails to satisfy an operating parameter.

1 . A method of operating a computer pointing peripheral, comprising: 
 capturing images of a support surface to perform navigational analysis to generate data indicative of movement of said computer pointing peripheral for output to a computer system;    analyzing at least one image characteristic;    modifying an image exposure time in response to said analyzing; and    modifying an intensity of illumination of said support surface when said image exposure time fails to satisfy an operating parameter.    
     
     
         2 . The method of  claim 1  wherein said modifying an intensity of illumination comprises: 
 modifying a drive current provided to an illumination device used to illuminate said support surface.    
     
     
         3 . The method of  claim 2  wherein said illumination device is a coherent light source.  
     
     
         4 . The method of  claim 2  wherein said illumination device is a highly directional light source.  
     
     
         5 . The method of  claim 1  wherein said analyzing at least one image characteristic determines whether an average pixel value is above a threshold value.  
     
     
         6 . The method of  claim 1  wherein said analyzing at least one image characteristic determines whether a maximum pixel value is above a threshold value.  
     
     
         7 . The method of  claim 1  wherein said modifying an exposure time modifies a shutter operation according to a number of clock cycles.  
     
     
         8 . The method of  claim 7  further comprising: 
 determining whether said number of clock cycles is within a predetermined range.    
     
     
         9 . A computer pointing peripheral, comprising: 
 an illumination element for illuminating a support surface;    an imaging array for capturing images of said support surface;    logic for processing said images to generate output signals that are indicative of movement of said computer pointing peripheral;    logic for analyzing said images for at least one characteristic;    logic for modifying an image exposure time of said imaging array, wherein said logic for modifying is responsive to said logic for analyzing; and    logic for modifying an intensity of illumination provided by said illumination element when said image exposure time fails to satisfy an operating parameter.    
     
     
         10 . The computer pointing peripheral of  claim 9  wherein said logic for modifying an intensity of illumination controls a drive current provided to said illumination element.  
     
     
         11 . The computer pointing peripheral of  claim 9  wherein said illumination element is a coherent light source.  
     
     
         12 . The computer pointing peripheral of  claim 9  wherein said illumination element is a highly directional light source.  
     
     
         13 . The computer pointing peripheral of  claim 9  wherein said at least one image characteristic is a parameter defining a threshold average pixel value.  
     
     
         14 . The computer pointing peripheral of  claim 9  wherein said at least one image characteristic is a parameter defining a maximum pixel value.  
     
     
         15 . The computer pointing peripheral of  claim 9  further comprising: 
 logic for generating a control signal to operate a shutter according to a number of clock signals, wherein said logic for generating operates in response to said logic for modifying an image exposure time.    
     
     
         16 . The computer pointing peripheral of  claim 15  wherein said logic for modifying an image exposure time determines whether said number of clock cycles is within a predetermined range.  
     
     
         17 . A computer pointing peripheral, comprising: 
 means for illuminating a support surface;    means for capturing images of said support surface;    means for processing said images to generate output signals that are indicative of movement of said computer pointing peripheral;    means for analyzing said images for at least one characteristic;    means for modifying an image exposure time of said imaging array according to said at least one characteristic; and    means for modifying an intensity of illumination provided by said means for illuminating when said image exposure time fails to satisfy an operating parameter.    
     
     
         18 . The computer pointing peripheral of  claim 17  wherein said means for analyzing determines whether an average pixel value fails to satisfy a predefined value.  
     
     
         19 . The computer pointing peripheral of  claim 17  wherein said means for analyzing determines whether a maximum pixel value fails to satisfy a predefined value.  
     
     
         20 . The computer pointing peripheral of  claim 17  wherein said means for modifying an intensity of illumination determines whether said image exposure time falls within a predetermined range.